Exothermic Vs Mechanical

[jbt260]

What is the most used (or best) method for bonding the GEC to a buried ground rod (assuming both are approved for direct burial)? We have always specified exothermic welds for below grade bonding to rods. Recently, we heard that inspectors are shying away from welds because they damage the conductor. Any thoughts?

 

[dereckbc]

Re: Exothermic Vs Mechanical

Mechanical will fail in a short period of time. I use two methods, exothermic, and Burndy Hy-Ground. The Burndy Hy-Ground product line is a irreversible compression connectors that require a hydraulic compression tool with dies to install.

Inspectors have no right to reject exothermic welds unless there is local admendments prohibiting them.

 

[sandsnow]

Re: Exothermic Vs Mechanical

Originally posted by jbt260:
Recently, we heard that inspectors are shying away from welds because they damage the conductor.

Maybe they saw some incorrectly installed connections?
Do they have some kind of industry report on this "damage"?

 

[tom baker]

Re: Exothermic Vs Mechanical

Erico likes Cadweld
Burndy likes compression.
They both have advantages and disadvantages.
Properly done, both are an excellent performance ground connection.
Cadwelds connnections can be UL listed.
For one or two connection types, cadweld is the less expensive, the one shots are the way to go. E

 

[rbalex]

Re: Exothermic Vs Mechanical

I concur with Dereck's post. There is no Code basis to reject exothermic welds. In fact, originally, exothermic was the only NEC recognized method. I was one of the original proposers to add "permanent, irreversible" mechanical connectors as an alternate to exothermic welds.

My concerns had nothing to do with exothermic welds damaging the conductors. My experience at the time was that, for #6 and larger conductors, exothermic welds often developed "pits" in the weld interior so the cross-sectional area, and therefore the current rating, was indeterminate. The larger the conductor, the greater probability of "pitting." Several manufactures said we were not making the welds correctly, so we invited them to demonstrate the proper procedure. They had identical results.

I would use either method today. I still prefer "permanent, irreversible" mechanical connections personally because I feel they are simpler to install. But if a contractor requested Engineer of Record permission to use exothermic I would probably approve it. I've never had such a request.

 

[tom baker]

Re: Exothermic Vs Mechanical

Good comment Bob. Exothermic takes the right mold, right shot, right weather, so there is more to go wrong. The molds can leak. But it is impressive to see!

 

[charlie]

Re: Exothermic Vs Mechanical

There are a some tricks that may be used with Cadweld. Use Aquaseal around to seal the mold and use a copper (not zinc) penny in place of the steel disk to add more copper to the mix.